This invention relates to refrigerating devices in general and, in particular, to a new and useful cooling device particularly for heat protective suits which includes a solid refrigerant disposed in heat exchange relationship with a heat exchange surface with a flexible intermediate layer between the solid refrigerant and the surface which is saturated with an intermediate liquid.
Heat protection systems such as used in personal heat protection suits, comprise a solid refrigerant, such as CO.sub.2 ice and a liquid, intermediate cooling agent. The latter is conducted through tubular flow channels incorporated in the suit near the body. It is by means of this intermediate cooling agent that a thermal equilibrium is maintained in which the body temperature cannot change beyond the physiologic limits.
The heat transfer between the solid refrigerant and the fluid intermediate cooling agent is very decisive for the safe functioning of such a system. This transfer can take place in a heat exchanger only at a separating point. The heat exchanger must also adapt to the basic requirement of low weight and volume since the suit is worn by the equipment carrier.
One known cooling vest, used as equipment to be worn individually, contains a circulating liquid cooling agent, such as a silicon oil, in cavities on its inside facing the body. The circulation is formed by cooling vest cavities in conjunction with external system components including a booster pump and a heat exchanger. The heat exchanger contains as the refrigerant, a CO.sub.2 dry ice filling in granulated form which, under sublimation, removes heat absorbed by the cooling vest from the circulating intermediate cooling agent. The CO.sub.2 gas formed thereby is utilized to operate the booster pump.
A contact pressure element ensures good heat transfer at the heat exchanger surfaces, and also in operation independent of position. The contact pressure element, which is moved by a compression spring, pushes the CO.sub.2 dry ice against the heat exchanger surfaces for reliable heat transfer and, at the same time, prevents the formation of a CO.sub.2 gas cushion which impedes the heat transfer. However, it is disadvantageous that, in the granule layer in contact with the heat exchanger surfaces, the interstices between the grains diminish the heat transfer due to the layer's grainy structure. This necessitates larger heat exchanger surfaces which thus become heavier and bulkier than would be necessary if the heat transfer were optimal (Dragerhaft 310, Jan./Apr. 1978, pages 17-24).